This section introduces aspects that may help facilitate a better understanding of the disclosure. Accordingly, these statements are to be read in this light and are not to be understood as admissions about what is or is not prior art.
Conjugated polymers are promising optoelectronic materials for next-generation flexible and printed electronics. Conjugated polymers are a class of polymers with delocalized π-orbitals along the polymer backbone. Extensive efforts have been put into the design and synthesis of conjugated polymers. A plethora of knowledge about how to rationally control their optical, electronic, and redox properties has been realized in the development of numerous conjugated polymers. In contrast, partially-conjugated semiconducting polymers with intentionally-placed, non-conjugated flexible linkages that allow conformation freedom along the polymer backbones have received little attention. There are two primary reasons. First, flexible linkages create high degrees of conformational and energetic disorder in polymer chains. Second, conjugation-break spacers (CBSs) disrupt the extended π-electron delocalization along polymer backbones. Conjugation-break spacers, also called non-conjugated spacers or non-conjugation spacers or non-conjugal spacers, are chemical groups that do not present pi-conjugation along the polymer backbone and connect two conjugated moieties through covalent bonds. In principle, both factors can have a negative influence on electronic properties, particularly for charge transport. On the other hand, high performance conjugated polymers are often plagued with poor solution-processability, a leading factor for batch-to-batch variations in both polymer synthesis and device fabrication. This limits applications of conjugated polymers in large scale flexible electronics. Conventionally, tuning solution-processability of polymers in organic solvents can be achieved by changing the size and shape of flexible solubilizing chains attached to polymer backbones. However, the modulation of polymer solution-processability and electronic performance turns out to be nontrivial as the factors that determine processability and electronic properties are incompatible. It should be noted that solution-processability is a term used to describe the desirable characteristics of the solution, namely adequate solubility of the polymer in this solvent, ability to make the solution as homogeneous as possible in terms the polymer concentration, and the ability of the solution to lend itself to depositing methods that provide uniform thickness and physical properties for films made from the solution.
Currently chlorinated solvents are utilized as solvents for polymer semiconductor materials for solution processing. These solvents are toxic. Further the existing polymer semiconductors do not lend themselves to melt-processing. Further, the existing polymer semiconductors do not lend themselves extrusion and lamination processing.
For the forgoing reasons, there exists a need for environmentally friendly approaches that can be applied to conjugated polymers to enhance their solution-processability as well as lending other types of processability for the conjugated polymers making them into useful polymer semiconductors for electronic and optoelectronic applications. Further there is need for melt processable polymers and polymers that lend themselves to extrusion and lamination processing.